Tailoring CuO nanostructures for enhanced photocatalytic property

► Various morphologies of CuO nanostructures were synthesized by hydrothermal method. ► PEG200 act as structure directing reagent with the synergism of alkalinity. ► The method provides a way to transform 1D to 2D and to 3D nanostructures. ► The morphology is not the factor to determine the photocatalytic performance. ► The high surface energy {−1 2 1} facets dominate the high photocatalytic performance.